Amplitude of solar wind density turbulence from 10--45 $R_{\odot}$

TL;DR

This study characterizes the amplitude of solar wind density turbulence and its variation with distance from the Sun and solar cycle, using occultation observations and structure function analysis.

Contribution

It provides a comprehensive analysis of $C_{N}^{2}$ and $rac{\delta N}{N}$ in the solar wind from 10 to 45 solar radii, incorporating observational constraints and turbulence models.

Findings

$C_{N}^{2}$ and $rac{\delta N}{N}$ vary systematically with heliocentric distance.

The turbulence amplitude shows dependence on the solar cycle.

The work offers a detailed profile of solar wind turbulence characteristics.

Abstract

We report on the amplitude of the density turbulence spectrum ($C_{N}^{2}$) and the density modulation index ($\delta N/N$) in the solar wind between $10$ and $45 R_{\odot}$. We derive these quantities using a structure function that is observationally constrained by occultation observations of the Crab nebula made in 2011 and 2013 and similar observations published earlier. We use the most general form of the structure function, together with currently used prescriptions for the inner/dissipation scale of the turbulence spectrum. Our work yields a comprehensive picture of a) the manner in which $C_{N}^{2}$ and $\delta N/N$ vary with heliocentric distance in the solar wind and b) of the solar cycle dependence of these quantities.